Page 2 of 6
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Troubleshooting
No Power at Thermostat
A
1. Remove the thermostat from its subbase. Set the multimeter to ‘Volts AC’ (V~) and measure
between the subbase ‘R’ (or ‘Rc’) and ‘C’ terminals. It should read between 23-28 volts.
If the thermostat has both ‘Rh’ and ‘Rc’ terminals
If the system has a single transformer
If the multimeter reads 0 volts
Problem:
The Common Maker and thermostat are installed but the thermostat is not receiving
power.
If the multimeter reads below 23 volts
If the system has two transformers (one for heating, one for cooling)
•
Thermostats typically require power on ‘Rc’ to function. The ‘Rc’ and ‘Rh’
terminals should be jumpered together to provide power to both the
thermostat and heating equipment.
•
Smart thermostats may have an internal jumper that connects ‘Rh’ and
‘Rc’. This is configured in the thermostat settings.
•
The power to the equipment should have been turned off during
installation. Ensure it was turned back on.
•
Check each wire nut for broken wires. Ensure the wire nut is tightened
enough stay on when lightly pulled.
•
Some equipment may have a control panel cabinet with a ‘door safety
switch’ that disconnects power while the cabinet door is open. Ensure
the door is closed while testing.
•
Check the fuse at the equipment to see if it was blown during installation.
If it did, check the Common Maker wiring for errors and replace the fuse.
•
If the problem still persists, proceed to the ‘Thermostat Cable Test’ (page 4).
•
Some equipment may not have a transformer large enough to power
a Wi-Fi thermostat. If the voltage drops below 23 volts when the
thermostat is connected and the equipment is on, a second transformer
will have to be installed. See diagram ‘C’ on the instructions.
•
The Common Maker must be installed on the cooling equipment. See
diagram ‘G’ in ‘Additional Wiring Diagrams’.
•
If the thermostat has a jumper between ‘Rh’ and ‘Rc’, remove it.
•
Smart thermostats may have an internal jumper that connects ‘Rh’ and
‘Rc’. This is configured in the thermostat settings.
